Brush holder for revolving brushes



April 2, 1929. J, os'r o 1,707,403 BRUSH HOLDER FOR REVOLVING BRUSHESFiled y 13. 1927 ZSheets-Sheet 1 April 2, 1929. J. K. KOSTKO 1,707,403

BRUSH HOLDER FOR REVOLVINGw BRUSHES 2 Sheets-Shee' Filed May 15. 1927;

d l ffrlfots'ika' UNITED STATES iii" PATENT err-ice s- EL R Re enues Baan Applieation filed May 13,

This invention relates to improvements in statmnary commutators andrevolving brush holders carrying brushes adapted to cooperate withstationery or with moving commutators.

The objects and featur s of this invention will appear from thedescription and drawings and will be more particularly po nted out inthe claims.

in the accon ipanying diagrammatic drawings 1 and 2 snow two views ofone embodiment of my invention, Figs. 3, 4: and 6., 7 show two views oftwo other embodiments, F shows one view of a fourth embodiment and Figs.8, 9 and O are explanatory diagrams.

lllferring more particularly to Figs. 1 and 52, moun ed on the revolvingshaft 2 of a motor generator is a spider 3 which carries any suitablenumber of brackets 9 insulatingly held to the spider 3 by means of thebolts 8. Each bracket 9 supports a pin 12 on which are pivotally mountedtwo pairs of scissor-like arms 10, 11 and 10, 11, one pair being"controlled by the coil spring 7, the other by the coil spring 7 and eachspring tending to close one pair of scissorlike arms.

The stationary member of the dynamoelectric machine is provided with anumber of brackets which support the stationary commutator 6. Thiscommutator is circular and of i -shaped cross-section. The stem of the Tis directed inwardly towards the shaft of the motor and the two sides ofthis stem, which are in planes perpendicular to the shaft, form theworking surfaces or faces of the st lonary commutator which may have anydesired numltier. of segments. These segments are radially insulated onefrom the other and held together by a metal ring 85 insulated from thecommutator segments by strips of insulation 21 and preferably shrunkover the properly assembled T-shaped ments of 6,. lhe ring '-5 iscarried by the bracket-3 20 and held in place by the ring 18 and thestuds 19. This commutator is connected to a winding which is not shownbut which is located on the stator or stationary member of thedynamoelectric machine.

@ppositely located brushes 4L, 5, which may be of carbon or any othersuitable material, cooperate in pairs with the two radial workfaces ofthe T-shaped commutator and are ly held in operative relation to saidfaces by the two pairs of scissor-like arms 1227. Serial in). 191,100.

10, 11 and 10, 11, loosely pivoted on 12, as shown in Fig. 1, andcontrolled by the springs 7 and 7". Each brush carries on its outer enda metal cap ll, 15 and a pin l6, 17 passes through each brush and itscap. Each pin runs approximately parallel to the working face of thecommutator, projects on each side of its brush and its axis is aboutparallel to a tangent to the outer circumference of the commutator. Thearms 10 and 1.0 engage with the pin 16 of the brush 4 located on oneside of the commutator segn'ients, while the arms 11, ll" similarlyengage with the pin 17 of the oppositely located brush The pins 16 and17 loosely fit int-o suitably shaped notches provided ineach of the armsas more clearly shown in Fig. 10. I

When the shaft 2 revolves 1t carrles w th it the brackets 9, the springcontrolled arms 10, 11, 10, ll and the brushes 4, 5 with which theycooperate. The commutator 6 is stationary. The brushes l, 5 may beconnected to a winding or windings on the revolving ember of themachine.

It is seen that relative movement between b ushes and the revolving;member is in no way hindered in an axial direction. Thus, if thecommutator stationary and the shaft moves axially to and fro due, forinstance, to end play the brushes remain in cooperative relation to thecommutator, in other Words the whole brush surface normally in contactwith a working face of the commutator remains contact with said facewhile the revolving member moves to and fro relative- 1y to the brushand in a direction at rightangles to the working face of the commutator.During such axial movement of the revolving member the hubs of the arms10, 11, 10, 11 move on the pin 12 and the notches in said arms move.onthe pins 16 and 17. Then the revolving member moves axially the axialilisplacement between original points of contact between'the pinsforming part of said brushes and the notches in the arms 10, 11, 10, 11,and between pin 12 and the hubs of arms, is very considerably less thanthe concurrent axial displacement of the revolving member. In Figs. 1.and 2 the centrifugal force acting on the brushes 4.: and 5 increasesthe pressure on the pins 12, 16, 17 but does not materially affect thepressure of the brushes; on the working faces of the commutater, A brushreadily removed for examination or replacement by pulling the corrponding a m. ver have th e mm tat to a sufficient extent. and slippingthe brush pin out of the notches in said arms.

It. will be readily understood that the working faces of the commutatorneed not be exactly at right an les to the axis of the machine or ofthat of the revolving member, the stem of the T may, for instance, havesomewhat converging instead of parallel sides. Furthermore, it is notnecessary to operate the brushes in groups of two. One of the brushes 4or 5 in Fig. 1 can, of course, be omitted.

In the embodiment shown in Figs. 3 and 4 a U-shaped member 31 is securedto the bracket 9 by means of the rivet 34: and prevented from turningabout said rivet by means of the pin 22. This U-shaped member forms abox-like brush holder adapted to guide the brush 5, provided with themetal cap 15, into operative relation with the radial working face ofthe con'nnutator 6. This commutator has but one working face and is ofL-shaped cross section. The brush is yieldingly pressed into surfacecontact with the commutator face by means of the lever 25 looselymounted on the pin 22 and under the control of the coil spring 26, oneend of which passes through and is held in the hole 32 provided in oneof the sides of the U-shaped member 31 while the other end of thisspring presses against the lever 25. Shoulders provided in the sides ofthe member 31 limit the travel of the brush in the direction of theshaft and the cross member of the U-shaped piece limits the travel ofthe brush in the opposite direction. The brush 5 is also under thecontrol of the spring 30, one end of which is attached to a hook held inthe cap while the other is attached to the hook 87 mounted on a pinpassing through the side members of 31. The spring 80 opposes theaction. of the centrifugal force on the brush 5 and is preferably sodimensioned that in normal operation the brush 5 floats between thestops limiting its radial movement.

In the arrangen'ient shown in Figs. 3 and L the revolving brush 5 isfree to remain in cooperative relation to the commutator face, in otherwords to retain a surface contact with said face, while the revolvingmember moves axially to and fro carrying the bracket 5) with it. Thisbrush is held in yielding con tact with the coi'iunutator face by thelever 25 and spring 26 and the ctfcct of the centrifugal force on brush5 is sutliciently counteracted by H 2 spring 30 to prevent said brushfrom being forced into intimate contact with the cross piece of themember 31. A considerable movement of the brush in an axial direction orof the revolving member along a line nor ma]. to the commutator facecorresponds to only a slight codirectional displacement between originalpoints of contact between parts of the mechanism which yieldingly holdthe brush in contact with the working face of the commutator and whichcounteract lhe action. of the centrifugal force on the brush. Thus, aconsiderable axial displacement of the revolving member causes but aslight movement between the hub of the lever 25 and the pin :22, aslightmovement between the point of the lever 25 and the cap 15 of thebrush and a slight movement between the ends of the spring 30 and thehooks with which said ends cooperate. By forcing the lever 25 back awayfrom the brush 5 it is possible. to withdraw the latter from the guidingelement 31 for inspection or replacement.

The arrangement shown in Fig. 5 differs from that illustrated in Fig 3and i: in that the lever 33 which is quite similar to the lever 25 ofFigs. 3 and 4: is so located with respect to the brush that it exerts onsaid brush a pressure having two components. One of these componentsyieldingly 'lorces aid brush into contact with the commutator .ace whilethe other opposes the action of the centri force on the brush To enablethe levy c to perform this dual. function a part of the brush 5 is cutaway so as to present a suitably inclined surface to the end of thelever 33. in 5 the sides of the guiding member 31 are shaped to suit then'iodiiicd position of the pin 22 with respect to the brush in theembodiment shown in Figs. 6 and 7 the member 23 is shaped to guide thebrush 3 into operative relation with the working face of the commutator6 of L-shaped cross section. The sidemen'ibers of the guide {33 arehook-shaped and engage with the pin held in the bracket 9. These bookslimit the travel of the giiiide 23 in a radial direction. This guide isheld approxinnitely in its 11o1 mal position by the flat spring @ne endof this spring is attached to the bracket at 86; the other end isprovided with extensions 28 which cooperate vith welders of the guide 23to prevent the books of the guide :25) from slipping off the pin 22. Thebrush 5 located within the upper end of the guid is held in yieldingcontact with the operating surface of the con'muitator by the lever 25loosely mounted on the pin and under the control of the spri g 26. Thetravel of the, brush in a radial direction is limited inwardly by a partof the spring 2? and ouiwardlv bv I i l 1 l :3 1 71f I 1'! a wee.rouuocu conical knoo 1 r atnu'heo m the guide i223 and cooperating witha suitable ufr memos ush gear and the revolving r or to retain itsoperative or surface contac with the working face of the commutator, letit be assumed that normally the conditions are as exagg-iratedlydepicted in Fig. 8. Let t e 'riginal points of contact between the brush5 and the centr fue'al force opposing means be M and N ind let theoriginal points of contact between the pin 22 and the hooks of t icguiding member 523 be M and N. If the revolving member now moves fromleft to right so as to bring the pin into that position with relation tothe working face of the counnutator 6 which is shown in Fig. 9, thebrusl 5 willmoveinwardly to someextent,willreiainitssurface contact withthe connnutator 6 and the conical mem ber 2 will be displaced on thebrush 5 bring about a displacement between the original points ofcontact M and N as well as a displacement between the original poin s ofcontact M and N as shown in Fig. 9. But, whereas the revolving member ofthe dyn amoelectric machine, and with it the pin 22, has movedrelatively to the commutator face through the distance a+b thecodirectional displacement between the original points of contact M andN amounts to about one tenth of that distance while that between theorig inal points of contact M and N amounts to oven'less. Obviously, thesame relative cisplacement would occur if the face of the commutatorwere correspondingly displaced with respect to the bracket 9. While therevolving member moves in the manner descr'bed in comiection with Figs.8 and 9, the original points of contact between the hub of the lever andthe pin 22 obviously undergo displacements quite similar to thosebetween the points M and N. In this manner the worl; of friction betweenparts of the brush gear and bet-ween the brush and the brush gear,caused by the said axial displacements, is greatly reduced andsluggishness of brush avoided without it being necessary to subject thebrush to such axial pressure as would involve undue friction lossesbetween the brush and the comnmtator. In orcer to remove brush 5 ofFigs. (5 and 7 for inspection or replacement, it necessary to pull thelever 25 away from the brush and slightly depress the spring 27 by meansof its wings 28. Depression of the spring 21' also permits of theremoval of the guide 23 by unhooking same from the pin 22.

It will be clear that various changes may be made in this disclosurewithout departing from the spirit of this invention, and it is,therefore, to be understood that this invention is not to be limited tothe specific details here shown and described.

lVhat I claim is:

1. In a. dynamoeleclric machine having a stationary and a revolvingmember, a com mutator on one member having a working respect to the brmember in o l y at right angles to th face a batantiall c axis of themachine, a brush carried by the other member and free to move withrespect to said other member substantially parallel to the axis of themachine, means for producing relative rotation between the brush and thecommutator, means for yieldinglypressing said brush into axial andsurface c dict wit the working face of the commutator, and means foropposing a radial movement of the brush, said named means beingconstit-uted that in case of relative axial displacement between thebrush and said oth member the axial displacement between original pointsof contact between brush and the most effective parts of the radialmovement opposing means is less than the relative axial displacementbetween the brush and the other member.

2. A commutator having a working face, a revolving brush cooperatingwith the commutator and free to move rola .ely to 3 support along a linenormal to the work 5 face of the commutator while retaining a surfacecontact witl said face, and mechanism for opposing the effect ofcentrifugal force on the brush along a line at angle to the normal tothe working face of inc commutator charactenzcd by the that in case ofrelative motion between the brush and its support in direction normal tothe coinmutator face the codirectional displacement between originalpoints of contact between parts of said mechanism is less than the con--current displacen'ient betwen the brush and its support.

3. In a dynamoelectric machine having a stationary and a revolvingmember, a commutator on one member having a working face substantiallyat right angles to the axis of the machine, a revolving brush carried bythe other member, said brush cooperating with the commutator and free tomove relatively to its support along a line normal to the work" ing faceof the commutator while retaining a surface contact with said face,means for limiting the radial displacement of the brush characterized bythe fact that in case of rclative motion between the brush and itssupport in a direction normal to the con'in'iutator face thecodirectional displacement betweei the brush and said limiting means isthan the concurrent displacement betw ion the brush and its support.

4:. A commutator having a working face, a revolving brush free to moverelatively to its support along a line normal to the coinmutator facewhile retaining a surface contact with said face, means for guiding ti obrush into operative relation with the commutator face, means foryieldingly pressing said brush into contact with the commutator face,and mechanism associated with the guiding means characterized by thefact that in case of relative motion between the brush and its supportin a direction normal to the commutator face the eodirectionaldisplacement between original points of conta t between parts 01 saidmechanism is less than the concurrent displacement between the brush andits support.

5. In a dynamoelectric machine, a commutator having a working "facesubstantially at right angles to the axis of the machine, a revolvingbrush. support, a brusl'i, means loosely pivoted on said support for revolving the brush and guiding it into operative relation with thecon'imutator iace, said brush beingfree to move relatively to thesupport substantially parallel to the axis of the machine, and means Foropposing a radial movement oil the brush said last nan'ied means beingso constituted that in case of elative axial motion between the brush and the support the cooirectional displacement between original points oicontact between brush and the most effective parts of the radialmovement opposing means is les than the axial displacement between thebrush and said support.

6. In a dynamoelectric machine, a stationary commutator having a workingface sub-- stantially at right angles to the axis of the machine, arevolving brush gear support comprising a pin, a brush, means looselyhinged on the pin for guiding the brush into operative relation to thecommutator face and pressed against said pin by centrifugal force, meansfor yieldingly pressing the brush into operative contact with thecommutator face, and retaining means providing a contact sun facebetween the brush and the guiding means adapted to take the centriihigalthrust of the brush on the guiding means, said surface being so formedand controlled that in case oi relative axial motion between the brushand the support the codirectional displacement between original pointsof contact between the lu'ush and said surface is less than the axialdisplacement between the brush an d the support 7. In a dyramoelectricmach ne, a stationary commutator loving a working tace substantially atright angles to the axis of the machine, a brush, a revolving brush gearadapted to guide the brush into operative relation to the commutatorface, and means for yieldingly pressing the brush into or warm tivecontact with the commutator and for counteracting the action oi thecentrifugal force on the brush.

S. In a oynamoeleetric n'iachinc, a stationary commutator havingaworlzing face substantially at right angles to the axis of the machine,a brush, a pin attached to the brush and approximately parallel to theworking face of the commutator, a revolving brush gear support, meansloosely pivoted on the support and loosely hinged about the l: rush pinfor yicldingly pressing the brush into operative contact with thecommutator face and for counteracting the etlfect of the centrifugalforce on the brush.

In testimony whercot I atlix my signature this 6th day of May, 1927.

JAROSLAVV K. KOSTKO.

